Embossing involves the creation of a three-dimensional image in a substrate such as paper, foil, laminate or other ductile material. The process involves passing the substrate through a nip formed by a die and a counter die. The die is sometimes referred to as a female die and has a desired pattern formed therein. The counter die, often called a male die, has a matching pattern that is received into the pattern of the die. The substrate is passed between the die and counter die and through a combination of heat and pressure has the desired pattern formed thereon. The pattern is formed at a level above that of the surrounding substrate. Although finding utility in a variety of applications, embossing is commonly applied to seals, postage stamps, and labels for food, beverages, cosmetics, cigars and wine.
One type of device currently used to form an embossing is a rotary device that includes a pair of hard embossing rolls that are cylindrical in shape. The rolls are typically made of steel or brass and have the desired pattern etched thereon. Although this type of device is capable of forming an embossing on a substrate, the cost for such a device is high and it generally takes a long amount of time to machine these types of rolls. Further, the cost to ship such a set of cylindrical rolls is high due to their weight and size.
An additional method of embossing currently used is photopolymer embossing. This process makes use of a pair of photopolymer embossing plates, that have a desired image imparted thereon, that are mounted to a pair of adjacent cylinders by double sided mounting tape. After application, one of the cylinders acts as a die and the other acts as a counter die. The substrate can be fed through the nip formed by the pair of photopolymer embossing plates to have an embossing formed thereon. Although this type of process works well for its intended purpose, embossing formed by photopolymer embossing plates generally has a low profile and poor edges. Also, this embossing technique is limited to forming only a two dimensional embossing and cannot form a three dimensional embossing. Further, adhesive on the double sided tape used to apply the photopolymer embossing plates to the cylinders is susceptible to breaking down and causing the photopolymer embossing plates to detach.
Another current process used to form an embossing employs a photopolymer metal backed embossing plate. This plate is a male die and is attached to a magnetic cylinder to be held thereon. A female die is not used. Instead, a rubber roller forms a nip with the photopolymer metal backed embossing plate and pushes the substrate down on top of this plate to form a two dimensional embossing thereon. Although this type of method is capable of forming an embossing, the resulting product generally has a very low profile in addition to poor height and edges.
It is also possible to create an embossing through the use of flat plates. These plates are generally made of brass, copper or magnesium. Male and female patterns are etched into the plates, and the substrate is positioned between the plates in order to be embossed. Embossing tools of this type are costly and are not suited for various types of manufacturing processes. As such, there remains room for variation and improvement within the art.